Critical care medicine
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Critical care medicine · Dec 1985
Resistance and inertia of endotracheal tubes used in infants during periodic flow.
To study the effects of a periodic pattern of gas flow on the dynamic behavior of infant endotracheal tubes, we measured the resistance (expressed as a function of gas flow) and inertia of endotracheal tubes of 2.5, 3.0, and 3.5-mm internal diameter under conditions of both periodic and quasisteady gas flow. We examined how resistance and inertia are affected by ventilatory rate, the direction of gas flow through the tube, and the expansion of the airway caliber at the junction of the tube and the trachea. ⋯ All tubes exhibited measureable inertia, as predicted from their small diameter. The resistive and inertial properties of the endotracheal tubes described in this report can be used to evaluate the contribution of the endotracheal tube to the dynamics of breathing in intubated infants.
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Critical care medicine · Dec 1985
Comparative StudyEffects on cerebral hemodynamics of resuscitation from endotoxic shock with hypertonic saline versus lactated Ringer's solution.
This study was carried out to determine whether 7.5% hypertonic saline (HSS) and lactated Ringer's solution restore cerebral hemodynamics comparably when used for resuscitation from endotoxic shock. Endotoxic shock was produced in 13 dogs by the iv administration of 1.5 mg/kg Escherichia coli endotoxin. After 90 min of shock, seven animals were resuscitated with lactated Ringer's solution, 60 ml/kg iv, and six with 7.5% HSS, 6 ml/kg iv. ⋯ With HSS, intracranial pressure was lower immediately after resuscitation (p less than .001) and one hour later (p less than .01). However, cerebral blood flow was not increased by either fluid and, due to hemodilution, cerebral oxygen transport decreased during resuscitation in both groups of animals. Thus, HSS restored systemic hemodynamics and maintained a lower intracranial pressure during resuscitation from endotoxic shock, but failed, as did lactated Ringer's solution, to restore cerebral blood flow and oxygen transport.
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The Biocuff is a new pressure device designed to overcome the problems associated with use of pneumatic cuffs and spring-driven devices. It consists of three modular elements: a sleeve, an air sac, and a booster. ⋯ The Biocuff is easy to handle and is quickly put into operation. It is most advantageous in situations requiring rapid infusion of large volumes of blood.